Late genitourinary toxicity in salvage radiotherapy for prostate cancer after radical prostatectomy: impact of daily fraction doses.

OBJECTIVE: To evaluate the impact of daily fraction doses on late genitourinary (GU) toxicity after salvage radiotherapy (SRT) for prostate cancer. METHODS: This multi-institutional retrospective study included 212 patients who underwent SRT between 2008 and 2018. All patients received image-guided intensity-modulated SRT at a median dose of 67.2 Gy in 1.8-2.3 Gy/fraction. The cumulative rates of late grade ≥2 GU and gastrointestinal (GI) toxicities were compared using Gray test, stratified by the ≤2.0 Gy/fraction (n = 137) and ≥2.1 Gy/fraction groups (n = 75), followed by multivariate analyses. The total dose was represented as an equivalent dose in 2-Gy fractions (EQD2) with α/ß = 3 Gy. RESULTS: After a median follow-up of 63 months, the cumulative rates of 5-year late grade ≥2 GU and GI toxicities were 14% and 2.5%, respectively. The cumulative rates of 5-year late grade ≥2 GU toxicity in the ≥2.1 Gy/fraction and ≤2.0 Gy/fraction groups were 22% and 10%, respectively (P = .020). In the multivariate analysis, ≥2.1 Gy/fraction was still associated with an increased risk of late grade ≥2 GU toxicity (hazard ratio, 2.37; 95% confidence interval, 1.12-4.99; P = .023), while the total dose was not significant. CONCLUSION: The present results showed that ≥2.1 Gy/fraction resulted in a higher incidence of late grade ≥2 GU toxicity in SRT. ADVANCES IN KNOWLEDGE: The impact of fraction doses on late GU toxicity after SRT remains unknown. The results suggest that higher fraction doses may increase the risk of late GU toxicity in SRT.

Impact of radiation doses on clinical relapse of biochemically recurrent prostate cancer after prostatectomy.

The relationship between radiation doses and clinical relapse in patients receiving salvage radiotherapy (SRT) for biochemical recurrence (BCR) after radical prostatectomy (RP) remains unclear. We identified 292 eligible patients treated with SRT between 2005 and 2018 at 15 institutions. Clinical relapse-free survival (cRFS) between the ≥ 66 Gy (n = 226) and < 66 Gy groups (n = 66) were compared using the Log-rank test, followed by univariate and multivariate analyses and a subgroup analysis. After a median follow-up of 73 months, 6-year biochemical relapse-free survival, cRFS, cancer-specific survival, and overall survival rates were 58, 92, 98, and 94%, respectively. Six-year cRFS rates in the ≥ 66 Gy and < 66 Gy groups were 94 and 87%, respectively (p = 0.022). The multivariate analysis revealed that Gleason score ≥ 8, seminal vesicle involvement, PSA at BCR after RP ≥ 0.5 ng/ml, and a dose < 66 Gy correlated with clinical relapse (p = 0.015, 0.012, 0.024, and 0.0018, respectively). The subgroup analysis showed the consistent benefit of a dose ≥ 66 Gy in patients across most subgroups. Doses ≥ 66 Gy were found to significantly, albeit borderline, increase the risk of late grade ≥ 2 GU toxicity compared to doses < 66 Gy (14% vs. 3.2%, p = 0.055). This large multi-institutional retrospective study demonstrated that a higher SRT dose (≥ 66 Gy) resulted in superior cRFS.

[Case of Long-Term Response to Radiotherapy for Intramedullary Spinal Cord Metastasis from Ovarian Cancer after Surgery].

Intramedullary spinal cord metastasis(ISCM)often causes spinal cord neuropathy and should be treated as an oncologic emergency. However, it recurs in most cases after treatment, ISCM is a disease with a very unfavorable prognosis. Herein, we report a successfully treated case of ISCM with emergent and high-dose radiotherapy. A 53-year-old woman had difficulty walking without assistance 2 years after surgery for ovarian cancer. She received emergent radiotherapy at a total dose of 50 Gy in 25 fractions. Her neurological symptoms dramatically improved over 3 weeks after radiotherapy. ISCM has been controlled using the imaging tests at 5 years after radiotherapy. We believe that both emergent and high-dose radiotherapy were effective for ISCM.

Comparison of Recurrence Patterns between Adenocarcinoma and Squamous Cell Carcinoma after Stereotactic Body Radiotherapy for Early-Stage Lung Cancer.

We compared recurrence patterns between adenocarcinoma (ADC) and squamous cell carcinoma (SCC) after stereotactic body radiotherapy (SBRT) for early-stage lung cancer. Patients with ADC and SCC histology, who were treated with SBRT for clinical stage IA1-IIA lung cancer at our institution, were included in the analysis. The rates of disease-free survival (DFS), overall survival (OS), local recurrence (LR), lymph node metastasis (LNM), and distant metastasis (DM) were calculated using the Kaplan-Meier method or the cumulative incidence function. Among the 204 patients analyzed, 138 and 66 were in the ADC and SCC groups, respectively. The median follow-up period was 60 months. The five-year DFS and OS rates were 57% vs. 41% and 69% vs. 48% in the ADC and SCC groups, respectively (p = 0.015 and 0.019, respectively). In the multivariate analysis, the histological type was not associated with DFS or OS. Five-year LR, LNM, and DM rates were 10% vs. 24%, 12% vs. 20%, and 25% vs. 27% in the ADC and SCC groups, respectively (p = 0.0067, 0.074, and 0.67, respectively). The multivariate analysis identified the histological type of SCC as an independent factor for LR (hazard ratio, 2.41; 95% confidence interval, 1.21-4.77; p = 0.012). The present results suggest that the risk of LR after SBRT is higher for SCC than for ADC.